氨气法合成聚天冬氨酸的合成工艺研究

Study on the synthesis process of polyaspartic acid by ammonia method

以液氨和马来酸酐为原料合成聚天冬氨酸,研究了马来酸酐与液氨的摩尔比、顺丁烯二酸铵盐合成温度和时间、聚合反应温度和时间以及水解pH等对聚丁二酰亚胺产率和聚天冬氨酸分子质量的影响。并用FTIR对合成的聚天冬氨酸的结构进行表征。结果表明,较佳的反应条件为:n(顺酐)∶n(液氨)=1∶1.2,顺丁烯二酸铵盐合成温度为85℃,反应时间为2 h,聚合反应温度为210℃,聚合反应时间为4 h,水解pH为9.0。在无催化剂条件下,聚丁二酰亚胺产率可高达95%以上,聚天冬氨酸重均分子质量高于7 500。

Polyaspartic acid is synthesized by using liquid ammonia and maleic anhydride as raw materials. The effects of the molar ratio between maleic anhydride and liquid ammonia,synthetic temperature and time for ammonium salt of maleic acid,polymerization temperature and time,and hydrolysis pH on the yield of polysuccinimide（ PSI） and average molecular weight of polyaspartic acid（ PASP） are studied. The obtained PASP is characterized by FTIR. The results show that the optimal reaction conditions include： molar ratio of maleic anhydride and liquid ammonia being 1 ∶1. 2,synthetic temperature and time of ammonium salt of maleic acid being 85℃ and 2 h,polymerization temperature and time being 210℃ and 4 h,and hydrolysis of PSI under ph = 9. Under appropriate conditions without catalyst,the yield of PSI can exceed 95% and the average molecular weight（ Mw） is higher than 7 500.